An air pollution alert is in effect for five Pennsylvania regions, including Berks County and the Lehigh Valley.

A Code Orange ozone alert is in effect Friday for Berks County/Lehigh Valley, Liberty-Clairton, Pittsburgh, the Susquehanna Valley, and Mercer County, the Department of Environmental Protection said in a release.

Young children, the elderly and those with respiratory problems such as asthma should limit outdoor activities.